The goal of this research is to determine the principles that underlie the interactions of key biological molecules. To do this, we will use the methods of x-ray crystallography to determine the three dimensional structures of selected systems. We are studying molecular complexes involved in the activation of transcription in E coli: DNA, the catabolite gene activator protein, and the alpha subunit of RNA polymerase. We are also studying RNA protein complexes that are involved in the influenza A infection. In addition, we are determining the structures of selected oligonucleotides in an attempt to understand the effects of sequence and environment on DNA structure.